Dielectric Properties of Polymer Nanocomposite Interphases Using Electrostatic Force Microscopy and Machine Learning

Abstract

Knowing the dielectric properties of the interfacial region in polymer nanocomposites is critical to predicting and controlling dielectric properties. They are, however, difficult to characterize due to their nanoscale dimensions. Electrostatic force microscopy (EFM) provides a pathway to local dielectric property measurements, but extracting local dielectric permittivity in complex interphase geometries from EFM measurements remains a challenge. This paper demonstrates a combined EFM and machine learning (ML) approach to measuring interfacial permittivity in 50 nm silica particles in a PMMA matrix. We show that ML models trained to finite-element simulations of the electric field profile between the EFM tip and nanocomposite surface can accurately determine the interface permittivity of functionalized nanoparticles. It was found that for the particles with a polyaniline brush layer, the interfacial region was detectable (extrinsic interface). For bare silica particles, the intrinsic interface was detectable only in terms of having a slightly higher or lower permittivity. This approach fully accounts for the complex interplay of filler, matrix, and interface permittivity on the force gradients measured in EFM that are missed by previous semianalytic approaches, providing a pathway to quantify and design nanoscale interface dielectric properties in nanodielectric materials.

Electrical and Dielectric Properties of Polymer-Metal Hybrid Nanocomposites - A Short Review

“…Engineered nanomaterials made with nanoscale dimensions are often categorized into four types: carbon, metal oxides, dendrimers, and composites. Composite is multiphase solid materials consist of a matrix and reinforcement or dispersed phase(s) [3][4]. With this understanding of composite materials, the nanocomposites (NCs) may be defined as a nanocomposite is a composite material wherein at least one of the reinforcements or dispersed phases has the dimension of the range 1 to 100 nm (1nm = 10 -9 m), that is, the nanophase.…”

“…Mechanical properties (e.g., modulus, strength, and dimensional stability) [2]. Thermal properties (e.g., conductivity, stability, and heat distortion temperature) [3]. Electrical properties (e.g., conductivity (resistivity) and capacitance) [4].…”